U.S. patent number 4,126,726 [Application Number 05/784,522] was granted by the patent office on 1978-11-21 for disc-shaped information carrier having information in the form of a beam-reflecting structure and a process for producing the same.
This patent grant is currently assigned to Polygram GmbH. Invention is credited to Horst Soeding.
United States Patent |
4,126,726 |
Soeding |
November 21, 1978 |
Disc-shaped information carrier having information in the form of a
beam-reflecting structure and a process for producing the same
Abstract
A disc-shaped information carrier for high-density storage, in
particular for video signals, has the information provided on both
sides of the carrier and stored in the form of a beam-reflecting
surface structure which is covered by a layer of translucent
material. A disc-shaped base element is formed by injection
molding, pressing, stamping or the like to exhibit a surface
structure corresponding to the information to be stored on both
sides thereof. Each side has a thin metallic coating applied
thereto which maintains the same surface profile and the
information structure is protected on each side with a layer of
transparent material.
Inventors: |
Soeding; Horst (Hanover,
DE1) |
Assignee: |
Polygram GmbH (Hamburg,
DE1)
|
Family
ID: |
5974992 |
Appl.
No.: |
05/784,522 |
Filed: |
April 4, 1977 |
Foreign Application Priority Data
Current U.S.
Class: |
369/275.1;
156/209; 156/272.2; 369/94; 427/304; 427/314; 427/508; 427/558;
428/163; 428/164; 428/409; 428/64.2; 428/913; G9B/7.194 |
Current CPC
Class: |
G11B
7/26 (20130101); Y10S 428/913 (20130101); Y10T
156/1023 (20150115); Y10T 428/24537 (20150115); Y10T
428/31 (20150115); Y10T 428/24545 (20150115) |
Current International
Class: |
G11B
7/26 (20060101); G11B 007/00 (); G11B 005/82 ();
B32B 015/08 (); B32B 015/20 () |
Field of
Search: |
;274/41.6S,41A,42R
;428/156,163,164,409,913 ;427/304,314,367,54 ;156/272,209 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Ansher; Harold
Attorney, Agent or Firm: Hill, Gross, Simpson, Van Santen,
Steadman, Chiara & Simpson
Claims
I claim:
1. An information carrier for high-density storage, comprising:
a base element including a pair of surfaces each having a surface
profile structure corresponding to the stored information;
a pair of metallic beam reflecting layers each carried on a
respective one of said surfaces and having the respective surface
profile on the outer metal surfaces; and
a pair of transparent layers each carried on a respective one of
said metallic layers
2. The information carrier of claim 1, wherein said base element
comprises a thermosetting material.
3. The information carrier of claim 1, wherein said base element
comprises:
a central layer having a pair of planar surfaces; and
a pair of information bearing layers each carried on a respective
one of said planar surfaces and each having a respective one of
said surface profile structures.
4. The information carrier of claim 3, wherein said central layer
comprises opague material.
5. The information carrier of claim 3, wherein said central layer
comprises an aluminum layer.
6. The information carrier of claim 1, wherein:
each of said metallic layers has a thickness in the range of 300 to
1000 A; and
each of said transparent layers has a thickness in the range of 200
to 400 .mu..
7. The information carrier of claim 1, wherein said carrier is
disc-shaped.
8. A process for producing an information carrier comprising the
steps of:
forming a surface structure on each side of a base element
corresponding to information to be stored;
applying a metallic coating on each of the sides while
maintaining
the same surface structure on the outer metal surfaces; and
applying a transparent coating over each of the metallic
coatings.
9. The process of claim 8, wherein the step of applying the
metallic coatings is further defined as vapor depositing the metal
coatings on the base element.
10. The process of claim 8, wherein the step of applying the
transparent coatings is further defined as covering the metallic
coatings with lacquer.
11. A process for producing an information carrier, comprising the
steps of:
forming surface profiles on opposite surface portions of a base
element to define the information to be stored;
hardening the profiled surface portions;
applying a beam-reflecting profiled metallic layer on each of the
surface profiles on the outer metal surfaces while maintaining the
same profiles; and
applying transparent protective coatings over the metallic
layers.
12. The process of claim 11, wherein the step of hardening is
further defined as:
heating the profiled surface portions.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an information carrier for
high-density storage, in particular for the storage of video
signals, in which the information is provided on both sides of the
carrier and stored in the form of a beam-reflecting surface
structure which is covered, in each case, by a layer of translucent
material.
2. Description of the Prior Art
An information carrier of the type mentioned above is known in the
art, for example reference may be taken to the German published
application No. 2,341,338, which corresponds to the British Pat.
No. 1,446,009 of Aug. 11, 1976 and the Australian Pat. No.
5,974,573 of Mar. 6, 1975. This prior information carrier comprises
two separate discs of transparent material which are connected
together by an intermediate layer and having their respective sides
provided with a beam-reflecting surface structure each of which
faces the other. With this structure, the information is read by an
optical scanning beam which penetrates from the outside through the
transparent carrier layer to the beam reflecting surface, where the
beam is reflected and modulated according to the profile of the
beam-reflecting surface. Here, the thickness of the transparent
carrier layer is not particularly critical because the scanning
beam is focused as precisely as possible in the information plane.
However, considerable demands are made on the homogeneity of the
transparent carrier material and in this respect certain
difficulties arise in the production of such information carriers
because material residues, called "tags", stick to the pressing die
and cause corresponding fault zones in the information carriers
which are made from these dies. Other material discrepancies are
caused by internal material stresses, bubbling or other harmful
phenomena which arise during the production process.
SUMMARY OF THE INVENTION
It is the primary object of the present invention to provide an
information carrier for signals that can be read optically and in
which the aforementioned discrepancies or fault zones do not have
an adverse effect on the reading process.
Starting with a disc-shaped information carrier of the general type
mentioned above, the above objective is achieved, according to the
present invention, by providing a disc-shaped base element which is
made of opaque material, for example, and which exhibits a surface
structure corresponding to the information contained therein on
both sides by providing the two sides of the base element with a
thin metallic coating which preserves the surface structure.
Finally, the metallic coatings are covered with a layer of
translucent material.
In one embodiment of the invention, the base element may be a
thermosetting layer having the surface profile information storage
structure on each side thereof.
In another embodiment of the invention, the base element may
comprise an unprofiled disc which is provided with a lacquer
coating on each side, the lacquer coating being embossed with the
stored information and hardened by the application of radiant
energy thereto, such as by ultraviolet light.
The unprofiled disc may be a transparent material, in which case
the lacquer layers may be irradiated from one side, with the
distant lacquer layer receiving the radiant energy via the other
lacquer layer and the intermediate transparent layer. With an
opaque central layer, such as aluminum, the lacquer layers must be
irradiated from respective sides.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the invention, its
organization, construction and operation will be best understood
from the following detailed description taken in conjunction with
the accompanying drawings, on which:
FIG. 1 is a greatly magnified sectional view of a portion of an
information carrier constructed in accordance with the present
invention;
FIG. 2 is also a greatly magnified sectional view of a portion of
another information carrier constructed in accordance with the
present invention;
FIG. 3 is a flow chart which describes the process for producing an
information carrier of the type illustrated in FIG. 1; and
FIG. 4 is a flow chart for a process for producing an information
carrier of the type illustrated in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 1 and 3, an information carrier and a process
for producing the same are illustrated. The information carrier
essentially comprises a disc-shaped base element 1 constructed of
an opaque material. On each side of the base element 1, there is a
surface structure corresponding to the information stored, the
surface structure being a profile which is produced by stamping,
pressing, injection molding or other suitable techniques. A
beam-reflecting metallic coating 2 of roughly 300 to 1000 A
thickness is provided over each surface profile of the base element
1 by vapor deposition or chemical processes. It will be appreciated
that the metallic coating reproduces and maintains the surface
profile and therefore the stored information. Finally, a
transparent lacquer coating 3 of about 200 to 400 .mu. thickness is
applied over each of the metallic coatings 2 in order to protect
the informatiom against scratches, dust and the like. The lacquer
coatings 3 form the entry and exit faces for the optical scanning
beam. In comparison with the carrier molded under the influence of
pressure and heat as known in the prior art, these lacquer coatings
offer considerable advantages with regard to their optical
properties because the chance of potential fault zones, caused by
internal material stresses, bubbling or other harmful phenomena,
are substantially reduced. Advantageously, the thickness of the
lacquer coatings 3 is selected such that dust particles, scratches,
etc, on the surface of the lacquer are so far outside the depth of
focus of the optical reproduction system that such surface faults
are no longer a nuisance. The total thickness of the information
carrier is about 1 to 1.5 mm.
Referring now to FIGS. 2 and 4, another embodiment of the
information carrier and its process of production are illustrated.
With respect to structure, only the base element differs from the
base element illustrated in FIG. 1. In FIG. 2, the basic material
for the base element is an unprofiled disc-shaped base plate 1'
which is provided on both sides with an information layer 1"
reproducing the information structure. The reproduction of the
information structure is carried out with the aid of an embossing
die, for example. The information layers 1" are preferably
constituted by lacquer coatings that can be set by the action of
radiant energy, for example UV light. Expediently, a transparent
base plate 1' is used with this production method because the
radiation source can then act on both information layers
simultaneously. In the alternative, however, an opaque base plate,
made of aluminum for example, can also be used. In this case, the
hardening process using ultraviolet light or other radiation is
carried out, not through the base plate, but from both sides using
a glass matrix in each case. After irradiation to harden the
lacquer coatings and set the information, the element is processed
in a manner similar to the device in FIG. 1 in that beam-reflecting
metallic coatings 2 are applied over the information layers 1"
reproducing and maintaining the same surface profiles, and the
metallic coatings are then covered with transparent lacquer
coatings 3.
Although I have described my invention by reference to particular
illustrative embodiments thereof, many changes and modifications of
the invention may become apparent to those skilled in the art
without departing from the spirit and scope of the invention. I
therefore intend to include within the patent warranted hereon all
such changes and modifications as may reasonably and properly be
included within the scope of my contribution to the art.
* * * * *